Thursday, April 28, 2011

Joining Practice Part II

Just got back from evening class. Practiced Fillet and Lug Brazing some more. More pictures!

Here is some improvement on my lugging and fillet brazing. The above joint is a fake lug, the cylinder to box joint is fillet brazed. Although I improved my technique a lot, I had the problem of having that white build up on the edge of the brass. The white matter is zinc chloride or zinc oxide or something like that... It appears when the brass starts to heat up to a considerable degree; the higher the temperature, the more zinc that becomes exposed. Though the white patina can be easily washed off, zinc also comes out of the brass in the form of a toxic gas which is fairly unhealthy to breath. It probably is indicative of me over-heating the steel anyway, so I should back off on the torch in the future.
 I got a little torch crazy. Here are all the sample welds up to this point welded together more or less... The assignment was to do one hollow form using oxy-acetlyne welding--which I did, but decided to do a little brass work too. Gussy it up, y'know.
Here is a joint similar to what you'd see on the bottom bracket of the bicycle. Fillet again.
Too much heat...
Hopefully my lug work will clean up to this point, as the clear-coat on my fixed gear reveals. FYI I did not do this, some poor factory worker in Japan during the late 70's did.
You can see the copper coming to the surface of the brass on part of these drop outs. I spy with my little eye some hidden Dura Ace... I also apologize for the fuzzy photo quality, I haven't really figured out focus on my camera yet.
The quintessential lug.

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